安装CAD2012总是会出现各种错误，不能安装，特别是.NET Framework Runtime 4.0安装错误。
单独安装dotNetFx40_Full_x86_x64.exe会提示更高级的版本已经安装。
解决办法：
1.打开安装文件夹中的“Setup.ini”
2.搜索“.NET”
3.将DOTNET BEGIN到DOTNET END之间的部分替换成以下代码，并保存：
#============= DOTNET Begin ===============
[DOTNET4]
PLATFORM=ALL
PRODUCT_NAME=.NET Framework Runtime 4.0
EXE_PATH=3rdPartyNET4wcudotNetFrameworkdotNetFx40_Full_x86_x64.exe
EXE_PARAM=/q
VC_FUNC=DotnetVerify
VC_SOURCE=SetupSetupUi.dll
VC_PARAM=.NET Framework 4 Full
VC_DESCRIPTION=Detecting .NET 4.0 Runtime
DISKCOST=80000000
IGNORE_FAILURE=YES
[DOTNET4LANG]
PRODUCT_NAME=.NET Framework Runtime 4.0 Language Pack
EXE_PATH=3rdPartyNET4wcudotNetFrameworkdotNetFx40LP_Full_x86_x64_%lang%.exe
EXE_PARAM=/q
EXE_LANGS=1036;1040;1031;1034;1046;1041;1042;2052;1028;1029;1038;1045;1049
DISKCOST=3000000
IGNORE_FAILURE=YES
[DOTNET35SP1]
PLATFORM=ALL
PRODUCT_NAME=.NET Framework Runtime 3.5 SP1
EXE_PATH=3rdPartyNET35SP1wcudotNetFrameworkdotnetfx35.exe
EXE_PARAM=/q /lang:ENU /norestart
VC_FUNC=DotnetVerify
VC_SOURCE=SetupSetupUi.dll
VC_PARAM=.NET Framework 3.5 SP1
VC_DESCRIPTION=Detecting .NET Runtime 3.5 SP1
DISKCOST=80000000
IGNORE_FAILURE=YES
ACTION=INSTALL
[DOTNET20]
PLATFORM=NATIVE
PRODUCT_NAME=.NET Framework Runtime 2.0
EXE_PATH=3rdParty\%platform%NET2NetFx20.exe
EXE_PARAM=/q:a /c:"install.exe /q"
VC_FUNC=DotnetVerify
VC_SOURCE=SetupSetupUi.dll
VC_PARAM=.NET Framework 2.0
VC_DESCRIPTION=Detecting .NET 2.0 Runtime
DISKCOST=80000000
IGNORE_FAILURE=YES
[DOTNET]
PLATFORM=ALL
PRODUCT_NAME=.NET Framework Runtime 4.0
EXE_PATH=3rdPartyNET4wcudotNetFrameworkdotNetFx40_Full_x86_x64.exe
VC_PARAM=4.0.30319
VC_DESCRIPTION=Detecting .NET 4.0 Runtime
IGNORE_FAILURE=YES
#============= DOTNET End ===============
4.重新执行安装文件即可。
另外要注意的是，安装文件的路径和安装路径中，不要出现中文名和空格等特殊字符。